As hardware for reproducing and storing high-resolution or high-quality video content is being developed and supplied, a need for a compression scheme for effectively encoding or decoding the high-resolution or high-quality video content is increasing.
In particular, since the amount of information contained in a digital video signal is very large, it is indispensable to compress video data so as to efficiently store, detect, and transmit the information.
Thus, many video-data compression techniques have been developed. A Joint Photographic Experts Group (JPEG) format which is an international standard still-image compression format has been introduced in relation to video compression techniques.
However, a compression rate according to the JPEG format is no higher than that of an image compression format that is widely compatible or other latest image compression formats.
Recently, technology of re-encoding a JPEG image to increase compression performance with the same image quality has been disclosed. In this technology, a JPEG image is re-encoded to reduce required memory and transmission costs.